DE102012211610B4 - Topology of a fully decoupled oscillator based on an LC resonant circuit for applications with low phase noise and high oscillation amplitude - Google Patents

Abstract

A resonant circuit based oscillator (100) comprising: one or more active devices; one or more passive components; and a tank circuit that is decoupled from the one or more active devices using at least one of the one or more passive devices, wherein a coupling ratio between the tank circuit and the one or more active devices is set to be a maximum value of a vibration amplitude of the tank circuit is limited based on a breakdown voltage of only the one or more passive devices, wherein the one or more passive devices comprise at least a first (123) and a second capacitor (124), the one or more active devices N-channel Metal oxide field effect transistors or bipolar transistors comprising a first and a second active device, each having at least one drain or a collector and a gate or base, and wherein the gate or the base of the first active device (131) with a since e of the first capacitor and the drain of the second active device (132) or collector of the second active device, the gate or base of the second active device (132) is connected to one side of the second capacitor (124) and the drain or the collector the first active device is connected and the resonant circuit (140) is connected between the other side of the first capacitor and the other side of the second capacitor to decouple the resonant circuit from the first and second active components.

Description

GOVERNMENT RIGHTS

This invention was made with government support under contract number: FA8650-09-C-7924 (Department of Defense Research Projects Authority (DARPA)). The government has certain rights to this invention.

BACKGROUND

Technical area

The present invention relates generally to information processing, and more particularly to a topology of a fully decoupled oscillator based on an LC resonant circuit for low phase noise, high amplitude oscillation applications.

Description of the Prior Art

Oscillator phase noise is a significant performance measure in many wireless and wireline communications applications, radars, sensors, imagers, data converters, etc. The power of each clocked system would benefit from a lower noise oscillator. One way to reduce the oscillator phase noise is to increase the amplitude of the oscillation. In a given technology, the maximum amplitude is determined by the breakdown voltage of the active devices (FETs, BJTs or other types of devices). Oscillator phase noise can also be reduced by using lower noise devices or higher breakdown voltage devices, lowering the temperature, and so forth.

A general term for oscillator noise is given by Leeson's formula as follows:

From this equation it can be seen that at given temperature T, oscillation frequency ω ₀ , offset from carrier Δω and Q-factor, the only way to reduce phase noise is to increase the signal power (P _sig ) (or equivalently the amplitude of the oscillation) increase, whereby the noise factor F is kept constant. Here k = 1.3806503 × 10 ^-23 m ² kg / s ² / K is the Boltzmann constant.

Within a given technology, increasing the amplitude-to-noise ratio is the most productive practical approach to solving this fundamental problem. It is important to emphasize that in general an active device with less noise also has a lower breakdown voltage. In addition, in virtually all technologies, the breakdown voltage of the active devices is much lower than the breakdown voltage of passive devices. It is also noted that the strength of some passive devices (such as metal-oxide-metal capacitors) can be controlled constructively to a certain extent.

The book "Semiconductor Circuit Technology" discloses the circuits and calculations of Colpitts oscillators in a collector circuit or with a differential amplifier (Tietze, U; Schenk Ch: Gamm E .: Semiconductor Circuit Technology, 13th Edition Berlin, Heidelberg: Springer- Verlag, 2010. 1515-1517; 1523-1525 - ISBN 978-3-642-01621-9).

In the US 6700451 B1 a voltage controlled oscillator with a cross-coupled cascode is disclosed. The oscillator comprises: a variable frequency oscillation circuit, first and second cascode coupled active devices coupled to the oscillation circuit, and third and fourth cascode coupled active devices coupled to the oscillation circuit, the first and second active devices at the third and fourth active devices are cross coupled. The invention provides lower drain-gate voltages, thereby reducing device errors.

In the US Pat. No. 8044733 B1 For example, an apparatus is disclosed that includes a voltage controlled oscillator. The oscillator includes a first transistor, a first resistor coupled between a first terminal of the first transistor and a first node, a first capacitor operatively coupled between a second terminal of the first transistor and the first node, and one connected to the first transistor first node functionally coupled second capacitor, wherein the first capacitor and the second capacitor form a capacitive voltage divider.

In the US 6946924 B2 discloses a voltage controlled oscillator having a pair of transistors, the transistors being coupled to a resonant circuit, the resonant circuit having a plurality of tuning diodes coupled in parallel with an inductor having electrically coupled anodes, the anodes being coupled to a common connection.

In the US 6204734 B1 For example, a method and apparatus for expanding a VCO tuning area are disclosed. A shunt inductance connected in parallel to a capacitance diode reduces an effective capacitance of the capacitance diode and increases a capacitance ratio. This increases the VCO tuning range without increasing tuning sensitivity variation and phase noise.

SUMMARY

The invention has for its object to provide an improved method for providing an improved oscillator-based oscillator and a corresponding oscillating circuit-based oscillator available.

The object underlying the invention is solved by the features of the independent claims. Preferred embodiments of the invention are indicated in the dependent claims.

In accordance with one aspect of the present principles, a resonant oscillator is provided. The oscillator includes one or more active devices, one or more passive devices, and a tank circuit that is decoupled from the one or more active devices using at least one of the one or more passive devices. A coupling ratio between the tank circuit and the one or more active devices is set such that a maximum value of a vibration amplitude of the tank circuit is limited based on a breakdown voltage of only the one or more passive devices.

According to one embodiment of the invention, the one or more passive devices comprise at least a first and a second capacitor, the one or more active devices being N-channel metal oxide field effect transistors or bipolar transistors comprising a first and a second active device, each having at least one drain or collector and a gate or base and wherein the gate or base of the first active device is connected to one side of the first capacitor and the drain or collector of the second active device, the gate or the base of the second active device is connected to one side of the second capacitor and the drain or collector of the first active device, and the oscillation circuit is connected between the other side of the first capacitor and the other side of the second capacitor to connect the oscillation circuit of the first and second second active n decouple components.

In accordance with another aspect of the present principles, a method is provided. The method includes providing a resonant oscillator having one or more active devices, one or more passive devices, and a tank circuit. The method further includes decoupling the tank circuit from the one or more active devices using at least one of the one or more passive devices. A coupling ratio between the tank circuit and the one or more active devices is set such that a maximum value of a vibration amplitude of the tank circuit is limited based on a breakdown voltage of only the one or more passive devices. According to an embodiment of the invention, the method further comprises exposing the one or more active devices to only a fraction of the maximum value of the oscillation amplitude.

According to an embodiment of the invention, the method further comprises determining the maximum value of the vibration amplitude based on a breakdown voltage and / or a breakdown current of at least one of the one or more passive components.

According to one embodiment of the invention, the one or more active devices comprise one or more MOSFETs, and the method further comprises independently biasing a drain and a gate of the one or more MOSFETs to control the oscillation amplitude of the tank circuit.

According to an embodiment of the invention, the one or more active devices comprise one or more bipolar transistors, and the method further comprises independently biasing a collector and a base of the one or more bipolar transistors to control the amplitude of oscillation of the tank circuit.

In yet another aspect of the present principles, a resonant oscillator is provided. The oscillator includes a resonant circuit. The oscillator also includes at least a first and a second capacitor. The oscillator further includes a first and a second active device. Each of the first and second active devices is an N-channel metal oxide field effect transistor or bipolar transistor and has at least one drain or collector and a gate or base. The gate or base of the first active device is connected to one side of the first capacitor and the drain or collector of the second active device. The gate or base of the second active device is connected to one side of the second capacitor and the drain or collector of the first active device. The tank circuit is connected between the other side of the first capacitor and the other side of the second capacitor to decouple the tank circuit from the first and second active devices.

In yet another aspect of the present principles, a resonant oscillator is provided. The oscillator includes a resonant circuit. The oscillator also includes at least first, second, third and fourth capacitors. The oscillator further includes a first and a second active device. Each of the first and second active devices is an N-channel metal oxide field effect transistor or bipolar transistor and has at least one drain or collector and a gate or base. The gate or base of the first active device is connected to one side of the first capacitor and one side of the third capacitor. The gate or base of the second active device is connected to one side of the second capacitor and one side of the fourth capacitor. The other side of the first capacitor is connected to the drain or collector of the second active device. The other side of the second capacitor is connected to the drain or collector of the first active device. The tank circuit is connected between the other side of the third capacitor and the other side of the fourth capacitor to decouple the tank circuit from the first and second active devices.

In accordance with another aspect of the present principles, a resonant oscillator is provided. The oscillator includes a resonant circuit. The oscillator also includes at least a first, a second, a third, a fourth capacitor and a fifth capacitor. The oscillator further includes a first and a second active device. Each of the first and second active devices is an N-channel metal oxide field effect transistor or bipolar transistor and has at least one drain or collector and a gate or base. The gate or base of the first active device is connected to one side of the first capacitor and one side of the fifth capacitor. The gate or base of the second active device is connected to one side of the second capacitor and the other side of the fifth capacitor. One side of the fourth capacitor is connected to the drain or collector of the first active device. One side of the third capacitor is connected to the drain or collector of the second active device. The other side of the first capacitor is connected to the other side of the third capacitor and one side of the tank circuit, and the other side of the second capacitor is connected to the other side of the fourth capacitor and the other side of the tank circuit to connect the tank circuit of the first and second circuits to decouple the second active components.

These and other features and advantages will become apparent from the following detailed description of the illustrative embodiments thereof, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

This disclosure provides details in the following description of preferred embodiments with reference to the following figures, wherein:

1 a topology 100 an oscillator based on an LC resonant circuit according to an embodiment of the present principles;

2 the replacement half circuit 200 for the topology 100 according to an embodiment of the present principles;

3 a depiction 300 for a simulation showing the stationary oscillation amplitude (Atank), gate voltage amplitude (Agate) and a variation of Gm over the cycle for the topology 100 according to an embodiment of the present principles;

4 another topology 400 an oscillator based on an LC resonant circuit according to an embodiment of the present principles;

5 the replacement half circuit 500 for the topology 400 according to an embodiment of the present principles;

6 yet another topology 600 an oscillator based on an LC resonant circuit according to an embodiment of the present principles;

7 the replacement half circuit 700 for the topology 600 according to an embodiment of the present principles;

8th yet another topology 800 an oscillator based on an LC resonant circuit according to an embodiment of the present principles;

9 the replacement half circuit 900 for the topology 800 according to an embodiment of the present principles;

10 another topology 1000 an oscillator based on an LC resonant circuit according to an embodiment of the present principles;

11 the replacement half circuit 1100 for the topology 1000 according to an embodiment of the present principles; and

12 a procedure 1200 for decoupling an oscillator based on an LC resonant circuit according to one embodiment of the present principles.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present principles are directed to a topology of a fully decoupled oscillator based on a coil-capacitor (LC) oscillator for low phase noise, high amplitude oscillatory applications.

According to one embodiment of the present principles, a manner is proposed for operating the oscillator such that the oscillation amplitude is not limited by the breakdown voltages of the active components. Instead, the LC resonant circuit is decoupled from the active devices and the coupling ratio between the LC resonant circuit and the active devices is set so that the oscillation amplitude can reach the maximum value determined only by the breakdown of the passive components. It is Z. For example, a scenario is provided in which the oscillator safely achieves a peak-to-peak difference amplitude of 40 V using active devices with 1 V breakdown voltages.

According to an embodiment of the present principles, the active devices in the oscillator are exposed to a small amount of full amplitude. This can be realized with a capacitive divider, a converter or a similar passive decoupling device. An additional advantage of the proposed approach is the reduced amount of noise introduced into the resonant circuit by the active devices. The overall phase noise is then lowered both by the increased amplitude and by the relatively lower noise input.

A variety of circuit topologies have been explored that can achieve the goal of reducing phase noise through the general techniques of increased oscillation amplitude and reduced noise input of the active devices into the resonant circuit. The topologies are explained and classified by the degree they accomplish the following objects, all of which are advantageous for achieving low phase noise: (1) increased oscillation amplitude in the LC oscillation circuit of the oscillator; (2) reduced introduction of noise of the active device into the LC resonant circuit; (3) improved quality (Q) of the resonant circuit (or reduced deterioration of the quality of the resonant circuit due to the active device and the load of the bias circuit); (4) independent biasing of the drain and gate (or collector and base) of the device to control the amplitude of vibration and the operating range of the device; and reduced waveform distortion. These above-mentioned advantages (1) to (4) result directly from Leeson's formula.

1 shows a topology 100 an oscillator based on an LC resonant circuit according to an embodiment of the present principles. The topology 100 an oscillator based on an LC resonant circuit contains a coil 111 , a coil 112 , a capacitor C _d 121 , a capacitor C _d 122 , a capacitor C _t 123 , a capacitor C _t 124 , an active component 131 , an active component 132 , an LC resonant circuit 140 and a power source 150 ,

The gate (or base) of the active device 132 is with one side of the capacitor C _t 124 , the drain (or collector) of the active device 131 , one side of the capacitor C _d 121 and one side of the coil 111 connected. The gate (or base) of the active device 131 is with one side of the capacitor C _t 123 , the drain (or collector) of the active device 132 , one side of the capacitor C _d 122 and one side of the coil 112 connected. The other side of the capacitor C _d 121 is with the other side of the capacitor C _d 122 connected. The other side of the coil 111 is with the other side of the coil 112 and connected to a voltage V _DD . The LC resonant circuit 140 is between the other side of the capacitor C _t 124 and the other side of the capacitor C _t 123 switched to the LC resonant circuit 140 from the active components 131 and 132 to decouple. The sources (or emitters) of the active devices 131 and 132 are with each other and with a power source 150 connected.

In the example of 1 are the active components 131 and 132 (N-channel) MOSFET. However, with the knowledge of the present principles provided herein, it should be recognized that one skilled in the art will appreciate the topology 100 from 1 with respect to other types of active devices, while retaining the inventive concept of the present principles. In addition, the same type of component z. As a MOSFET can be used, but with a p-channel version is used. These as well as further variations on the circuit elements of the topology 100 are readily determined and implemented by one skilled in the art with the knowledge of the present principles provided herein. In the topology 100 the LC resonant circuit becomes a position between the gates of the devices 131 and 132 , isolated by the capacitors C _t shifts.

2 shows the spare half circuit 200 for the topology 100 according to an embodiment of the present principles. The half circuit 200 contains a coil 211 , a capacitor 221 , a resistor R _t 291 , a capacitor C _t 124 , a capacitor C _d 121 , an active component 131 and an inverting device 281 , The sink 211 , the capacitor 221 and the resistance R _t 291 concern the LC resonant circuit 140 , In detail, the coil represents 211 the inductance component of the LC resonant circuit 140 , the capacitor 221 represents the capacitance component of the LC resonant circuit 140 and R _t 291 represents the losses in the LC resonant circuit 140 , Although elements of one half of the topology 100 for the half circuit 200 with the reference numerals of the figure being kept in agreement with it, one skilled in the art will readily recognize that the values of the same elements are different from the topology 100 the complete circuit opposite the half circuit 200 may nevertheless be readily determined by one of ordinary skill in the art having the benefit of the present principles provided herein. A stationary condition is determined according to the following:

It can be seen that the oscillation amplitude of the resonant circuit is represented by the ratio C _d / (C _d + C _t ) = 1 / k on the gates of the active components 131 and 132 is split. The resonant circuit is of the active components 131 and 132 decoupled, and the capacitive divider allows a higher amplitude vibration without the possibility of breakthrough at the gates of the components. An additional one Advantage to topology 100 is that the drain current noise is not completely through the resonant circuit 140 flows. Instead, part of the drain current noise flows through the series circuit of C _t and R _t and part through C _d . If one defines 1 / n as the fraction of the drain current noise flowing into the oscillation circuit, n ≈ (Z _Cd + Z _Ct + R _t ) / Z _Cd = (C _t + C _d + R _t * sC _d * C _t ) / C _t .

The capacitive divider in 1 , which is formed of the capacitors C _t and C _d , reduces the load on the active device in the resonant circuit 140 , therefore, the quality Q of the resonant circuit 140 degraded to a lesser extent than in the case of a cross-coupled oscillator and there is less waveform distortion.

3 shows a representation 300 for a simulation, the stationary oscillation amplitude (Atank), the gate voltage amplitude (Agate) and the variation of Gm over the cycle for the topology 100 according to one embodiment of the present principles. The x-axis represents the amplitude fluctuation at the transistor gates or optionally at the resonant circuit and the y-axis represents the large signal transconductance. In the example of 3 are k = 1.1 and n = 1.2.

4 shows another topology 400 an oscillator based on an LC resonant circuit according to an embodiment of the present principles. The topology 400 The oscillator based on an LC resonant circuit contains a coil 411 , a coil 412 , a capacitor C _d 421 , a capacitor C _d 422 , a capacitor C _t 423 , a capacitor C _t 424 , a capacitor C _c 425 , a capacitor C _c 426 , an active component 431 , an active component 432 , an LC resonant circuit 440 and a power source 450 ,

The gate (or base) of the active device 431 is with one side of the capacitor C _c 426 and one side of the capacitor C _t 423 connected. The gate (or base) of the active device 432 is with one side of the capacitor C _c 425 and one side of the capacitor C _t 424 connected. The other side of the capacitor C _c 426 is with the drain (or collector) of the active device 432 , one side of the capacitor C _d 422 and one side of the coil 412 connected. The other side of the capacitor C _c 425 is with the drain (or collector) of the active device 431 , one side of the capacitor C _d 421 and one side of the coil 411 connected. The other side of the capacitor C _d 421 is with the other side of the capacitor C _d 422 connected. The other side of the coil 411 is with the other side of the coil 412 and a voltage V _DD connected. The LC resonant circuit 440 is between the other side of the capacitor C _t 423 and the other side of the capacitor C _t 424 switched to the LC resonant circuit 440 from the active components 431 and 432 to decouple. The sources (or emitters) of the active devices 431 and 432 are with each other and with a power source 450 connected.

In the example of 4 are the active components 431 and 432 (N-channel) MOSFET. However, with the knowledge of the present principles provided herein, it should be recognized that one skilled in the art will appreciate the topology 400 from 4 with respect to other types of active devices, while retaining the inventive concept of the present principles. In addition, the same type of component z. As a MOSFET can be used, but with a p-channel version is used. These and other variations on topology circuit elements 400 are readily determined and implemented by one skilled in the art with the knowledge of the present principles provided herein. The topology 400 decouples the LC resonant circuit 440 from the terminals of the active devices, providing a possibility to increase the amplitude of oscillation both at the gate (or at the base) and at the drain (or at the collector) beyond the breakdown limits of the device, while at the same time reducing the effects of non-linearity of the device be reduced both at the gate and at the drain.

5 shows the spare half circuit 500 for the topology 500 according to an embodiment of the present principles. The half circuit 500 contains a coil 511 , a capacitor 521 , a resistor R _t 591 , a capacitor C _c 425 , a capacitor C _d 421 , a capacitor C _t 424 , an active component 431 and an inverting device 481 , The sink 511 , the capacitor 521 and the resistance R _t 591 refer to the LC resonant circuit 440 , In detail, the coil represents 511 the inductance component of the LC resonant circuit 440 , the capacitor 521 represents the capacitance component of the LC resonant circuit 440 and R _t 591 represents the losses in the LC resonant circuit 440 , Although elements of one half of the topology 400 for the half circuit 500 By keeping the reference numerals of the figure consistent therewith, one skilled in the art will readily recognize that the values of the same elements are different from the topology 400 with full circuit to the half circuit 500 However, they will nevertheless be combined with the findings of the findings provided here simply determines the principles of the present. Again, 1 / n represents the proportion of the drain current noise flowing into the oscillation circuit, and 1 / k represents the voltage dividing ratio from the oscillation circuit to the device gates, where n≈ (Z _Cc + Z _Ct + R _t + Z _Cd ) / Z _Cd = ( C _t C _d + C _d C _c + sR _t C _d C _{C t} + C _t C _c ) / C _t C _c and k ≈ (C _t + C _k ) / C _t , where C _k = C _c C _d / (C _c + C _d ). The stationary state is determined according to the following equation:

The topology 400 provides an increase in vibration amplitude using two different techniques. Capacitor feedback ensures that even when the non-linearity of the device transductance limits the amplitude of oscillation at the gate / base, the amplitude at the resonant circuit 440 by a factor k is greater than this limit. In addition, the non-linearity of the device is reduced, thereby increasing the oscillation amplitude even at the gate / base for a given amount of introduced noise of the active device. In addition, the vibration amplitude is due to the complete decoupling of the resonant circuit 440 from the active components 431 and 432 not by the breakdown voltage of these components 431 and 432 limited.

In summary, there are the following advantages of topology 400 : (1) the oscillation amplitude is increased by the oscillation circuit gate (base) return ratio k; (2) the amplitude is also increased from Agate to Atank as a result of the Gm linearization of a smaller variation of the drain voltage as in 3 shown; (3) the resonant circuit is completely decoupled from the active devices and therefore can withstand much larger voltage fluctuations; (4) only a fraction of the noise of the active device is introduced into the resonant circuit; (5) only a fraction of the noise from the bias circuitry flows into the resonant circuit; and (6) the quality of the oscillation circuit is not degraded by the fact that the MOSFETs enter the triode operating region, thereby causing less distortion and improving the phase noise. The benefits (2) and (6) are in full BJT versions of this topology 400 Less dominant over MOSFET versions.

6 shows another topology 600 an oscillator based on an LC resonant circuit according to an embodiment of the present principles. The topology 600 The oscillator based on an LC resonant circuit contains a coil 611 , a coil 612 , a capacitor C _t 623 , a capacitor C _t 624 , a capacitor C _c 625 , a capacitor C _c 626 , a capacitor C _g 627 , an active component 631 , an active component 632 , an LC resonant circuit 640 and a power source 650 ,

The gate (or base) of the active device 631 is with one side of the capacitor C _c 626 and one side of the capacitor C _g 627 connected. The gate (or base) of the active device 632 is with one side of the capacitor C _c 625 and the other side of the capacitor C _g 627 connected. The other side of the capacitor C _c 626 is with the drain (or collector) of the active device 632 , one side of the capacitor C _t 624 and one side of the coil 612 connected. The other side of the capacitor C _c 625 is with the drain (or collector) of the active device 631 , one side of the capacitor C _t 623 and one side of the coil 611 connected. The other side of the coil 611 is with the other side of the coil 612 and a voltage V _DD connected. The LC resonant circuit 640 is between the other side of the capacitor C _t 623 and the other side of the capacitor C _t 624 switched to the LC resonant circuit 640 from the active components 631 and 632 to decouple. Sources (or emitters) of active devices 631 and 632 are with each other and with a power source 650 connected.

In the example of 6 are the active components 631 and 632 (N-channel) MOSFET. However, with the knowledge of the present principles provided herein, it should be recognized that one skilled in the art will appreciate the topology 600 from 6 with respect to other types of active devices, while retaining the inventive concept of the present principles. In addition, the same type of component z. As a MOSFET can be used, but with a p-channel version is used. These and other variations on topology circuit elements 600 are readily determined and implemented by one skilled in the art with the knowledge of the present principles provided herein. The topology 600 shifts the LC resonant circuit 640 at a location between the device drains, isolated by capacitors C _t .

7 shows the spare half circuit 700 for the topology 600 according to an embodiment of the present principles. The half circuit 700 contains a coil 711 , a capacitor 721 , a resistor R _t 791 , a capacitor C _c 625 , a capacitor 2 · C _g 627 , a capacitor C _t 623 , an active one module 731 and an inverting device 781 , The sink 711 , the capacitor 721 and the resistance R _t 791 refer to the LC resonant circuit 640 , In detail, the coil represents 711 the inductance component of the LC resonant circuit 640 , the capacitor 721 represents the capacitance component of the LC resonant circuit 640 and R _t 791 represents the losses in the LC resonant circuit 640 , Although elements of one half of the topology 600 for the half circuit 700 By keeping the reference numerals of the figure consistent therewith, one skilled in the art will readily recognize that the values of the same elements are different from the topology 600 with full circuit to the half circuit 700 Nevertheless, they are nevertheless determined with the knowledge of the knowledge provided here of the present principles. By comparison with the half circuit 500 shows the half circuit 700 clearly that the voltage division ratio of the resonant circuit 640 is larger compared to the component gates compared to the resonant circuit.

That is, the proportion of the resonant circuit voltage at the component gates is smaller (by 1 / k), where k ≈ (C _l + C _d ) / C _l where C _l = C _c C _t / (C _c + C _t ). Conversely, the proportion of the resonant circuit voltage at the component gate is greater than in 5 and is given by (C _t + C _k ) / C _t where C _k = C _c C _d / (C _c + C _d ). Thus, the topology represents 600 a stronger G _m linearization than the topology 400 because the fluctuation at the drain is relatively lower, resulting in less nonlinearity. However, the feedback ratio to the gate is relatively larger for the topology 600 in comparison to the topology 400 Therefore, the amplitude on the resonant circuit increases as a result of this feedback ratio. Therefore, these two topologies represent 600 and 400 a possibility of compromise between the two techniques of increasing the amplitude depending on the device characteristics and the requirement for a particular design.

Because z. For example, in practical implementations, the nonlinearity of MOSFETs is highly dependent on the variation in drain voltage is the topology 400 with its lower voltage fluctuation suitable for MOSFET implementations. Considering BJT versions of the same topology 400 For example, the collector voltage variation does not affect the BJT non-linearity as significantly as the fluctuation at the node of the highly nonlinear base voltage. That is why the amplitude magnification in the topology makes 600 from the large resonant circuit gate feedback ratio (k) the topology 600 Especially suitable for BJT versions.

8th shows another topology 800 an oscillator based on an LC resonant circuit according to an embodiment of the present principles. The topology 800 The oscillator based on an LC resonant circuit contains a coil 811 , a coil 812 , a capacitor C _d 821 , a capacitor C _d 822 , a capacitor C _t 823 , a capacitor C _t 824 , a capacitor C _c 825 , a capacitor C _c 826 , a capacitor C _g 827 , an active component 831 , an active component 832 , an LC resonant circuit 840 and a power source 850 ,

The gate (or base) of the active device 831 is with one side of the capacitor C _t 823 and one side of the capacitor C _g 827 connected. The gate (or base) of the active device 832 is with one side of the capacitor C _t 824 and the other side of the capacitor C _g 827 connected. One side of the capacitor C _c 825 is with the drain (or collector) of the active device 831 , one side of the capacitor C _d 821 and one side of the coil 811 connected. One side of the capacitor C _c 826 is with the drain (or collector) of the active device 832 , one side of the capacitor C _d 822 and one side of the coil 812 connected. The other side of the coil 811 is with the other side of the coil 812 and a voltage V _DD connected. The other side of the capacitor C _t 823 is with the other side of the capacitor C _c 826 and one side of the LC tank circuit 840 connected. The other side of the capacitor C _t 824 is with the other side of the capacitor C _c 825 and the other side of the LC tank circuit 840 connected to the LC resonant circuit 840 from the active components 831 and 832 to decouple. Sources (or emitters) of active devices 831 and 832 are with each other and with a power source 850 connected.

For exemplary purposes, the active devices are 831 and 832 represented as bipolar transistors. However, it should be recognized that in topology 800 instead, MOSFETs may be used instead of the transistors, while retaining the spirit of the present principles. These as well as further variations on the circuit elements of the topology 800 are readily determined and implemented by one of ordinary skill in the art having the benefit of the present principles provided herein.

9 shows the spare half circuit 900 for the topology 800 according to an embodiment of the present principles. The half circuit 900 contains a coil 911 , a capacitor 921 , a resistor R _t 991 , a capacitor C _c 825 , a capacitor C _d 821 , a capacitor C _t 824 , a capacitor 2 · C _g 827 , an active component 831 and an inverting device 981 , The sink 911 , the capacitor 921 and the resistance R _t 991 concern the LC resonant circuit 840 , In detail, the coil represents 911 the inductive component of the LC resonant circuit 840 , the capacitor 921 represents the capacitive component of the LC resonant circuit 840 and R _t 991 represents the losses in the LC resonant circuit 840 , Although elements of one half of the topology 800 for the half circuit 900 with the reference numerals of the figure retained accordingly, one skilled in the art will readily recognize that the values of the same elements are different from the topology 800 the complete circuit opposite the half circuit 900 However, they may nevertheless be readily determined by one of ordinary skill in the art having the benefit of the present principles provided herein.

The topology 800 has the same advantages as the topology mentioned above 400 on. This topology 800 also provides an extra degree of freedom for the choice of variables and therefore provides better control over the performance specifications for this design. That means in comparison to the topology 400 adds the topology 800 add an additional capacitor (see 9 With 5 ), which now provides freedom in selecting total capacitive load, bias tuning, and feedback ratios (ie, there are 4 capacitors and 4 specifications). This is particularly useful in bipolar implementations where a smaller variation of the base voltage is desired due to higher device transconductance and greater non-linearity in the base-emitter circuit.

10 shows another topology 1000 an oscillator based on an LC resonant circuit according to an embodiment of the present principles. The topology 1000 The oscillator based on an LC resonant circuit contains a coil 1011 , a coil 1012 , a capacitor C _d 1021 , a capacitor C _d 1022 , a capacitor C _t 1023 , a capacitor C _t 1024 , a capacitor C _c 1025 , a capacitor C _c 1026 , a capacitor C _g 1027 , an active component 1031 , an active component 1032 , an LC resonant circuit 1040 and a power source 1050 ,

The gate (or base) of the active device 1031 is with one side of the capacitor C _c 1026 , one side of the capacitor C _t 1023 and one side of the capacitor C _g 1027 connected. The gate (or base) of the active device 1032 is with one side of the capacitor C _c 1025 , one side of the capacitor C _t 1024 and the other side of the capacitor C _g 1027 connected. The other side of the capacitor C _c 1026 is with the drain (or collector) of the active device 1032 , one side of the capacitor C _d 1022 and one side of a coil 1012 connected. The other side of the capacitor C _c 1025 is with the drain (or collector) of the active device 1031 , one side of the capacitor C _d 1021 and one side of the coil 1011 connected. The other side of the coil 1011 is with the other side of the coil 1012 and a voltage V _DD connected. The LC resonant circuit 1040 is between the other side of the capacitor C _t 1023 and the other side of the capacitor C _t 1024 switched to the LC resonant circuit 1040 from the active components 1031 and 1032 to decouple. Sources (or emitters) of active devices 1031 and 1032 are with each other and with a power source 1050 connected.

In the example of 10 are the active components 1031 and 1032 (n-channel) MOSFETs. However, with the knowledge of the present principles provided herein, it should be recognized that one skilled in the art will appreciate the topology 1000 from 10 with respect to other types of active devices, while retaining the inventive concept of the present principles. In addition, the same type of component z. As a MOSFET can be used, but with a p-channel version is used. These and other variations in the circuit elements of the topology 1000 will be readily determined and implemented by one skilled in the art with the knowledge of the present principles provided herein.

11 shows the spare half circuit 1100 for the topology 1000 according to an embodiment of the present principles. The half circuit 1100 contains a coil 1111 , a capacitor 1121 , a resistor R _t 1191 , a capacitor C _c 1025 , a capacitor C _d 1021 , a capacitor C _t 1024 , a capacitor 2 · C _g 1027 , an active component 1031 and an inverting device 1181 , The sink 1111 , the capacitor 1121 and the resistance R _t 1191 concern the LC resonant circuit 1040 , In detail, the coil represents 1111 the inductive component of the LC resonant circuit 1040 , the capacitor 1121 represents the capacitive component of the LC resonant circuit 1040 and R _t 1191 represents the losses in the LC resonant circuit 1040 , Although elements of one half of the topology 1000 for the half circuit 1100 with the reference numerals of the figure maintained accordingly, one skilled in the art will readily recognize that the values of the same elements are different from the topology 1000 the complete circuit opposite the half circuit 1100 However, they may nevertheless be readily determined by one of ordinary skill in the art having the benefit of the present principles provided herein.

In the replacement half circuit 1100 can be recognized that the topology 1000 also has 4 capacitors and thus has complete complexity in total capacitive load, bias tuning and feedback ratios. In fact, the topology 800 and the topology 1000 in the sense that one circuit can be converted to the other by merely making a change to the value of the capacitors C _c , C _d , C _t and C _g . Which circuit is used depends on which results in a given application more advantageous and easily realizable capacitor values.

In all of the previously explained replacement half circuits (ie the 2 . 5 . 7 . 9 and 11 ), it was assumed that the bias coils between Vdd and the drains of the devices have a very high impedance, and they have been omitted for ease of analysis. However, detailed simulations show that the resonant frequency in the drain circuit is important because it affects the amplitude of oscillation and the phase noise. The oscillation frequency is determined mainly by the resonant frequency of the LC resonant circuit, but the oscillation amplitude is largest and the phase noise the lowest when the resonant frequency of the drain circuit can be tuned to a frequency just below the oscillation frequency. The optimum resonant frequency of the drain circuit is empirically observed when it is about 70 to 90% of the oscillation frequency. For this reason, it is advantageous to take measures to jointly tune both the resonant frequency of the LC resonant circuit and the resonant frequency of the drain circuit.

TABLE 1 shows a summary of topologies and corresponding advantages according to one embodiment of the present principles. That is, TABLE 1 summarizes the various topologies of voltage controlled oscillators (VCO) discussed above and compares their advantages (and disadvantages). The four aspects compared include the vibration amplitude (A), the noise introduced into the resonant circuit (N); the load quality factor of the resonant circuit due to the influence of the transconductor (Q); and the waveform distortion due to a variable resistance in the loaded oscillation circuit (D). These aspects have a direct influence on the phase noise performance of the VCO. The mechanism for improving / changing these parameters for the different VCOs is mentioned in parentheses. Additional comments regarding these topologies are also highlighted in the "Comment" column. It can be seen from TABLE 1 that the proposed architectures improve these aspects (A, N, Q, and D) of the VCO as compared to prior art cross-coupled topologies. As a consequence, the new topologies provide different mechanisms to achieve low phase noise performance. TABLE 1 also provides an intuition of compromises between these topologies. The selection of a specific topology can be made by the specific requirements for this design. TABLE 1 topology advantages FIG. Comments 100 A → 4 Increases (feedback), no breakthrough problems N → proportion of active, proportion of bias Q → degraded (less than cross-coupled) D → Smaller distortion than cross-coupled 1, 2 The bias network can be tuned to a value close to the oscillation frequency to improve phase noise. 400 A → Increases (feedback, gm limit) no breakthrough problems N → proportion of active, proportion of bias Q → not deteriorated D → minimum distortion 4, 5 Emphasis on gm linearization The bias network can be tuned to a value close to the oscillation frequency to improve phase noise. 600 A → Increases (feedback, gm limit) no breakthrough problems N → proportion of active, proportion of bias Q → not deteriorated D → minimum distortion 6, 7 Stress on Amplitude Magnification from Feedback Ratio The bias network can be tuned to a value close to the oscillation frequency to improve phase noise. 800 A → Increases (feedback, gm limit) no breakthrough problems N → proportion of active, proportion of bias Q → not deteriorated D → minimum distortion 8, 9 Complete freedom in the choice of all parameters. The bias network can be tuned to a value close to the oscillation frequency to improve phase noise. 1000 A → Increases (feedback, gm limit) no breakthrough problems N → proportion of active, proportion of bias Q → not deteriorated D → minimum distortion 10, 11 Different maximum values for topology 800 (depending on the design, perhaps easier implementation). Complete freedom in the choice of all parameters. The bias network can be tuned to a value close to the oscillation frequency to improve phase noise.

12 is a procedure 1200 for decoupling an oscillator based on an LC resonant circuit according to an embodiment of the present principles. The decoupling is particularly advantageous for applications with low phase noise and high oscillation amplitude.

In step 1210 For example, an oscillator based on an LC resonant circuit is provided that has one or more active components, one or more passive components, and an LC resonant circuit. In step 1220 For example, the LC resonant circuit is decoupled from the active devices using at least one of the one or more passive devices. In step 1220 For example, a coupling ratio between the LC oscillation circuit and the one or more active devices is set so that a maximum value of the oscillation amplitude is limited based on a breakdown voltage of only the one or more passive devices.

Claims (11)

Oscillator-based oscillator ( 100 ), comprising: one or more active devices; one or more passive components; and a tank circuit that is decoupled from the one or more active devices using at least one of the one or more passive devices, wherein a coupling ratio between the tank circuit and the one or more active devices is set to be a maximum value of a vibration amplitude of the tank circuit is limited on the basis of a breakdown voltage of only one or more passive components, wherein the one or more passive components at least a first ( 123 ) and a second capacitor ( 124 ), the one or more active devices are N-channel metal oxide field effect transistors or bipolar transistors comprising first and second active devices, each having at least one drain or collector and a gate or base, and wherein the gate or base of the first active device ( 131 ) with one side of the first capacitor and the drain of the second active component ( 132 ) or collector of the second active device, the gate or the base of the second active device ( 132 ) with one side of the second capacitor ( 124 ) and the drain or the collector of the first active component is connected and the resonant circuit ( 140 ) is connected between the other side of the first capacitor and the other side of the second capacitor in order to decouple the oscillator circuit from the first and second active components. A resonant circuit based oscillator according to claim 1, wherein the plurality of active devices are exposed to only a part of the maximum value of the oscillation amplitude. The resonant circuit based oscillator according to claim 1, wherein the maximum value of the oscillation amplitude is set on the basis of a breakdown voltage of at least one of the plurality of passive components. The resonant circuit based oscillator of claim 1, wherein the plurality of passive devices comprise a passive decoupling device. The resonant circuit based oscillator according to claim 1, wherein a drain and a gate of the plurality of MOSFETs are independently biased to control the oscillation amplitude of the oscillation circuit. The resonant circuit based oscillator according to claim 1, wherein a collector and a base of the plurality of bipolar transistors are independently biased to control the oscillation amplitude of the oscillation circuit. Oscillator-based oscillator ( 400 ), comprising: one or more active devices; one or more passive components; and a tank circuit that is decoupled from the one or more active devices using at least one of the one or more passive devices, wherein a coupling ratio between the tank circuit and the one or more active devices is set to be a maximum value of a vibration amplitude of the tank circuit is limited on the basis of a breakdown voltage of only one or more passive components, wherein the one or more passive components comprise at least a first, a second, a third and a fourth capacitor, the one or more active devices N-channel Metal oxide field effect transistors or bipolar transistors are the first ( 431 ) and a second active component ( 432 ), each having at least one drain or collector and a gate or base, and wherein the gate or base of the first active device (12) 431 ) with one side of the first capacitor ( 426 ) and one side of the third capacitor ( 423 ), the gate or base of the second active device ( 432 ) with one side of the second capacitor ( 425 ) and one side of the fourth capacitor ( 424 ), the other side of the first capacitor is connected to the drain or collector of the second active component, the other side of the second capacitor is connected to the drain or collector of the first active component, and the tank circuit ( 440 ) is connected between the other side of the third capacitor and the other side of the fourth capacitor in order to decouple the oscillator circuit from the first and second active components. Oscillator-based oscillator ( 800 ), comprising: one or more active devices; one or more passive components; and a resonant circuit ( 840 ), which is decoupled from the one or more active devices using at least one of the one or more passive devices, wherein a coupling ratio between the tank circuit and the one or more active devices is set such that a maximum value of a vibration amplitude of the tank circuit on the Basis of a breakdown voltage of only the one or more passive components is limited, wherein the one or more passive components at least a first ( 823 ), a second ( 824 ), a third ( 826 ), a fourth ( 825 ) and a fifth capacitor ( 827 ), wherein the one or more active devices are N-channel metal oxide field effect transistors or bipolar transistors comprising a first and a second active device each having at least one drain or collector and a gate or base, and wherein the gate or base of the first active device ( 831 ) is connected to one side of the first capacitor and one side of the fifth capacitor, the gate or the base of the second active component ( 832 ) is connected to one side of the second capacitor and the other side of the fifth capacitor, one side of the fourth capacitor is connected to the drain or collector of the first active device, one side of the third capacitor is connected to the drain or collector of the second active device , the other side of the first capacitor is connected to the other side of the third capacitor and one side of the tank circuit, the other side of the second capacitor to the other side of the fourth capacitor and the other side of the tank circuit is connected to decouple the tank circuit from the first and second active components. A method comprising: providing a resonant oscillator ( 100 ) having one or more active devices, one or more passive devices, and a tank circuit; and decoupling the tank circuit from the one or more active devices using at least one of the one or more passive devices; and wherein a coupling ratio between the tank circuit and the one or more active devices is set such that a maximum value of a vibration amplitude of the tank circuit is limited based on a breakdown voltage of only the one or more passive devices, the one or more passive devices at least a first ( 123 ) and a second capacitor ( 124 ), the one or more active devices are N-channel metal oxide field-effect transistors or bipolar transistors having a first ( 131 ) and a second active component ( 132 ), each having at least one drain or collector and a gate or base, and wherein the gate or base of the first active device is connected to one side of the first capacitor and the drain of the second active device or collector of the second active device , the gate or base of the second active device is connected to one side of the second capacitor and the drain or collector of the first active device, and the tank circuit is connected between the other side of the first capacitor and the other side of the second capacitor the oscillating circuit circuit ( 140 ) to decouple from the first and second active devices. Oscillator-based oscillator ( 100 ), comprising: a tank circuit; at least a first and a second capacitor; and a first ( 131 ) and a second active component ( 132 Each of which is an N-channel metal oxide field effect transistor and a bipolar transistor and has at least one drain or collector and a gate or base, wherein the gate or base of the first active device is connected to one side of the first capacitor. 123 ) and the drain or collector of the second active device is connected, the gate or the base of the second active device with a side of the second capacitor ( 124 ) and the drain or collector of the first active device is connected and the resonant circuit is connected between the other side of the first capacitor and the other side of the second capacitor to the resonant circuit ( 140 ) to decouple from the first and second active devices. Oscillator-based oscillator ( 400 ), comprising: a resonant circuit ( 440 ); at least a first ( 426 ), a second ( 425 ), a third ( 423 ) and a fourth capacitor ( 424 ); and a first ( 431 ) and a second active component ( 432 Each of which is an N-channel metal oxide field effect transistor and a bipolar transistor and has at least one drain or a collector and a gate or a base, wherein the gate or the base of the first active device with one side of the first capacitor and a Side of the third capacitor is connected, the gate or the base of the second active device is connected to one side of the second capacitor and one side of the fourth capacitor, the other side of the first capacitor connected to the drain or collector of the second active component, the the other side of the second capacitor is connected to the drain or collector of the first active device, and the resonant circuit is connected between the other side of the third capacitor and the other side of the fourth capacitor to decouple the resonant circuit from the first and second active components.

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